An active matrix LCD device has the advantages of portability, low power consumption, and low radiation, and has been widely used in various portable information products such as notebooks, personal digital assistants (PDAs), video cameras and the like. Furthermore, the active matrix LCD device is considered by many to have the potential to completely replace CRT (cathode ray tube) monitors and televisions.
FIG. 7 is an abbreviated block diagram of certain parts of a typical active matrix LCD. The LCD 100 includes a liquid crystal (LC) panel 110, a gate driving circuit 120, a data driving circuit 130, and a timing control circuit 140, a light source 160, and a backlight module driving circuit 170. The backlight module driving circuit 170 drives the light source 160 to emit light beams for illuminating the LC panel 110. The timing control circuit 140 is used to control the gate driving circuit 120 and the data driving circuit 130. The gate driving circuit 120 provides a plurality of scanning signals to the LC panel 110. The data driving circuit 130 provides a plurality of gradation voltages to the LC panel 110 when the LC panel 110 is scanned.
An image shown on a display screen of the active matrix LCD 100 is refreshed (i.e. replaced by a new identical image) at a predetermined frequency. In particular, the LCD 100 normally works with a predetermined refresh rate such as sixty hertz, seventy-five hertz, or another similar refresh rate. When a frequency of ambient light is changed from a first frequency such as fifty-five hertz to a second frequency such as seventy-five hertz, the LCD 100 does not adjust the refresh rate thereof to adapt to the frequency of the ambient light. Thus a user may find that his or her eyes easily become tired.
What is needed, therefore, is an LCD that can overcome the above-described deficiency.